Without a vaccination programme, the model estimated a total of 501,644 varicella cases and 27,341 varicella-related complications. Vaccination of toddlers (12 to 18 months) reduced the cases to 93,783 and complications to 5,041, vaccination in adolescents reduced cases to 450,081 and complications to 23,959, and vaccination in both groups reduced cases to 88,751 and complications to 4,761.
From the societal perspective, with no vaccination, the average annual cost of varicella was approximately EUR 100 million (81% indirect costs) and with vaccination of toddlers and both groups the costs were less than EUR 50 million. From the national health service perspective, the average annual cost of vaccination compared with no vaccination ranged from EUR 4,030,698 for adolescents to 7,965,639 for both age groups.
From the societal perspective, all the vaccination strategies provided a positive benefit-to-cost ratio (the intervention cost more, but became cost saving after the intervention); the ratio ranged from 2.60 (1.66 discounted) for adolescents to 3.47 (2.13 discounted) for toddlers. From the national health service perspective, the return on investment did not indicate net savings; the values ranged from 0.36 (0.21 discounted) for adolescents to 0.67 (0.38 discounted) for toddlers.
The benefit-to-cost ratios and return on investment results remained consistent in direction through univariate and multivariate sensitivity analyses.